Crude preparations from species in the Dumontiaceae extracted in citrate phosphate buffer when added to cell cultures or mice prior to or simultaneous with inoculation by herpes simplex virus have been reported to inhibit herpes simplex virus, but when cells or animals were treated after inoculation with herpes simplex virus, no significant inhibition of the virus infection was observed (Deig, et al. 1974: Ehresmann, et al. 9175; Hatch, et al. 1977; Deig, et al. 1977; Ehresmann, et al. 1977; Richards, et al. 1978; Deig, et al. 1979; Hatch, et al. 1979; Ehresmann, et al. 1979). Results given in this present disclosure show improvement by extraction with water. We also show that, contrary to the findings cited in the above literature, treatment of cell cultures or of animals with aqueous extracts of algae two hours after inoculation with herpes simplex virus inhibits the virus infection. Additionally, contrary to results given by Deig, et al. 1974, the present finding is that acetone and chloroform solvent extracts from Cryptosiphonia woodii have anti-herpes activity as shown in in vitro assays.
The water extraction is different from previously known methods since no buffering salts were added. Water extracts have a pH 4.5 to pH 5.5 during the first extraction of the alga. All previous extractions from Cryptosiphonia woodii cited in the above literature have been made in a pH 7.0 citrate phosphate buffer. This is essentially an alkaline buffer at pH 7 and it will extract any organic acids including those of high molecular weight. Simple water extracts result in solutions of pH 4.5 to pH 5.5 which could contain acid soluble bases. This chemical difference is corroborated by the biological differences found. For instance, the citrate phosphate buffered extract of Crytosiphonia woodii was cited by Deig, et al (1974) as blocking cell receptor cites indicating a lack of post-infective activity in vitro against herpes simplex virus. In later publications (Richards, et al 1978; Hatch, et al 1979), it was concluded that algal extracts has inhibitory value against herpes simplex virus only if cell monolayers or mice were treated with extracts prior to infection. In contrast, our findings show that water extracts from Cryptosiphonia woodii inhibit herpes simplex virus when applied after infection of cell monolayer cultures.
Previously, mouse in vivo assays of preparations from Farlowia mollis (Richards, et al. 1978), and Cryptosiphonia woodii (Hatch, et al. 1979) showed prophylactic, but no therapeutic antiviral efficacy. In our hands, the antiviral extract from Cryptosiphonia woodii described herein shows therapeutic value in vivo by decreasing intravaginal herpetic lesions in guinea pig assays when applied after virus infection.
In their attempts to characterize the active component in Constantinea simplex (Hatch, et al. 1979), Cryptosiphonia woodii, and Farlowia mollis (Deig, et al. 1974), previous researchers suggested that a polysaccharide or glycoprotein was involved, however, the antiviral compound was not isolated. Participation of a protein was suggested based on heat lability and on observed decrease of in vitro activity when C. simplex extracts were treated with proteolytic enzymes (Hatch et al. 1979). In this report, we shall disclose the results of purifications of extracts from C. woodii and assays of some of the fractions in vitro which lead us to conclude that a polysaccharide (with glucose and galactose units) is the active component. Results also given in the present disclosure show that in the in vivo guinea pig vaginitis model, the whole aqueous extracts derived from Cryptosiphonia woodii are active on post-infection treatment.